Atmospheric nozzle for fuel injection system



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J ZN l 1 Mw /////\7///// United States Patent C) ATMOSPHERIC NOZZLE FOR FUEL INJECTION SYSTEM Arthur W. Case, Rochester, Mich., assigner to General Motors Corporation, Detroit, Mich., a corporation of Delaware v The present invention relates to an improved atmospheric nozzle for use with a fuel injection system of the mass air flow type. More particularly the present in- 'vention is an improvement over the atmospheric 'nozzle construction of the type shown in copending application Serial No. 512,175 Homfeld et al., filed May 3, 1955, now abandoned.

The .principle of operation of the present atmospheric nozzle -is the same as that set forth in the aforenoted copending application and the purpose of the present invention is to achieve a simplified atmospheric nozzle as Well as a less expensive method for its manufacture.

As brought out in the aforenoted application, the atmospheric nozzle is an extremely important and vulnerable part of the yfuel injection system in which it is embodied. As a consequence great care has been taken to insure the proper manufacture of such nozzles. While the manufacture of such nozzles has been greatly improved to insure satisfactory operation, they have continued to remain a relatively costly item even when produced in quantity. Accordingly, the present invention is directed to an improved and simplified nozzle which may be inexpensively manufactured.

It is the purpose of the present invention to provide a simplified multi-part nozzle construction in which the air and fuel metering portions are individually manufactured and simply assembled.

The details as well as other objects and advantages of the present invention will be apparent from a perusal of the description which follows.

In the drawings:

Figure 1 is a sectional view through an assembled fuel nozzle;

Figure 2 is a partially sectioned side view showing the nozzle components disassembled;

Figure 3 is a modified form of fuel orifice construction; and

Figure 4 is an enlarged partial sectional view showing the assembled fuel nozzle.

An atmospheric nozzle includes an air metering member 12 and a fuel supplying and metering member or tube 14. The air metering member 12 is originally formed of tubular stock having an external `diameter of the size shown in portion 16 as viewed in Figure 1. The stock is thereafter reduced, in any suitable manner, to provide tubular end portions 18 and 20.

As best seen in Figure 2 the enlarged portion 16 disposed -between the cylindrical end sections 18 and 20 is slabbed off or flattened to provide side wall portions 22 and 24 which are parallel and spaced apart a distance substantially equal to the diameter of reduced tubular portion 20. An enlarged air passage or bore 26 is thereafter diametrically drilled through portion 16.

Tubular end portion 18 is longitudinally drilled or otherwise formed to provide an enlarged passage 28 which terminates in an orifice 30 communicating with air pas- "ice sagev 26. The other tubular end portion 20 is similarly formed to provide a longitudinal passage 32 coaxially related to longitudinal passage 28. Passage 32 'terminates in a tapered seat portion 34 also communicating with the air passage 26 iuaxially spaced relation to the air metering orifice 30.

The fuel metering member 14 istubular in forni and has its inner end spun over to provide'l a tapered portion 36 corresponding to the tapered seat 34 provided in the longitudinal passage 32 of member 12. While not necessarily limited thereto, the tapered portion 36 of tube 14 andthe tapered seat 34 are desir-ably formed to provide an included angle of approximately After spinning over the end of tube 14 to provide the tapered portion 36, the tapered portion is then drilled to provide a centrally disposed fuel metering orifice'38 therein.

Having properly Vprovided the fuel metering orifice in.

tube 14 thetube is thereafter inserted within the longitudinalpa'ssage Y32 of'member 12 so that the tapered end portion 36 will reside within the tapered seat 34 of passage 32. As best seen in Figure l, when the members 12 and 14 are assembled the tapered end 36 of tube 14 projects slightly within the air passage 26 such that the fuel meter-ing orifice 38 will pass the metered fuel stream directly into the air passage. As in the aforenoted copending application, the-fuel stream from the fuel metering nozzle 38 is targeted through the atmospheric reference air nozzle 30 and in general ows uninterruptedly there-` through. It is apparent that the tapered relationship between seat 34 and tube portion 36 provides a simple yet extremely accurate fuel nozzle center-ing and longitudinal positioning means. In this way passage 32 may be made with sufficient clearance for the easy assembly of tube 14 therein and yet insure proper centering of the fuel orifice 38 for accurate targeting through orifice 30. As illustrated in Figure 4, the outside diameter of the fuel metering member 14 is less than the diameter of the longitudinal passage 32 in the reduced tubular end portion 20, so that a clearance space 42 is provided between the wall of the passage 32 and the member 14.

Once the tube member 14 is properly seated within the air metering member 12, the members are secured to-V gether as by soldering as shown generally at 40.

In the event it is desired to form the fuel metering por* tion of the nozzle by a machined process rather than by spinning as in the form shown in Figures 1 and 2, resort may be made to the modification of Figure 3 in which a plug 40 is adapted to be mounted in the end of a tube 42. Plug 40 is machined at one end to provide a sleeve portion 44 and a shoulder 46 while the other end 48 is formed with a taper the included angle of which is again 90. A longitudinal passage 50 is formed in plug 40 which terminates in an orifice passage 52.

To assemble the nozzle of -Figu-re 3, the sleeve portion 44 of plug 40 is inserted within tube 42 until shoulder 46 abuts the end of tube 42. Thereafter the plug and tube are inserted within passage 32 of member 20 until the tapered end 48 again seats within the conical seat 34. The clearance between sleeve 44 and tube 42 may be such as to retain the plug 40 in position by a press fit.

Briefly the operation of the atmospheric nozzle is as follows: fuel under pressure is supplied through tube 14 from where it passes through orifice 38 as a stream across air passage or chamber 26 and is targeted through air metering orifice 30. The fuel then continues through passage 28 where it is introduced into the individual cylinder induction passage, not shown, adjacent the cylinder of the engine. Since the end of the nozzle is exposed to manifold vacuum the effect of the latter on the quantity of fuel supplied through the nozzle is eliminated since the 3 A, vacuum force is dissipated by the atmospheric air in passage 26.

It will be seen that a simplified tfuel nozzle construction results when made in accordance with the above teachings. v

I claim:

A fuel nozzle for a fuel injection system comprising a first member having a pair of axially spaced portions intermediate which' is aflat sidedportion, an enlarged 'boreformed transversely of said lat sided portion, a first longitudinally extending passage formed in one of said axially spaced portions and 'terminating in an oriiice communicating with said bore, a second longitudinal passage formed in said other axially spaced portion in coaxial relation to said iirstpassage, vsaid second Vpassage including avtapered orifice centering `seat communicating with said bore, a second tubular member of lesser diameter disposed in spaced relationship Within said second longitudinal passage, an end portion of said second tubular member tapered correspondingly to and adapted to seat within the tapered seat of' said second longitudinal passage to provide the only means of centering and aligning said second tubular member in said second longitudinal passage, an orifice formed in the tapered end of said second tubular member and disposed in coaxially spaced relation with the orifice formed in said first longitudinal passage, and means without said second longitudinal passage for retaining said tapered tubular end portion in abutting engagement with said tapered seat.

i I References Cited in the file of this patent UNITED STATES PATENTS Y 943,684 Johnston Dee. 21,1909 1,237,965 Smith Aug. 21, 1917 1,490,164 Edhnlm Apr. 15, 1924 1,723,955 shepherd et 'a1 Aug. 6, 1929 2,252,122 Gordon et al. Aug. l2, 1941 2,252,958 Bicknell Aug. 19, 1941 2,511,213 Leslie June 13, 1950 2,630,304 Rivoche Mar. 3, 1953 yFOREIGN PATENTS 664,749 Y. Great Britain nf 1952 Germany of 1937 

